Scintillator panel and radiation detector

ABSTRACT

A scintillator panel 10 includes a substrate 11 having a substrate main surface 11a, a substrate rear surface 11b, and a substrate side surface 11c; and a scintillator layer 12 having a scintillator rear surface 12b formed of a plurality of columnar crystals, a scintillator main surface 12a, and a scintillator side surface 12c. The substrate side surface 11c and the scintillator side surface 12c are substantially flush with each other. In the substrate 11, an angle A1 between the substrate rear surface 11b and the substrate side surface 11c is smaller than 90 degrees.

TECHNICAL FIELD

The present invention relates to a scintillator panel and a radiationdetector.

BACKGROUND ART

As technologies in this field, technologies disclosed in PatentLiterature 1 to Patent Literature 4 are known.

Patent Literature 1 discloses a fluorescent plate. The fluorescent platehas a fluorescent body substrate and a fluorescent layer formed on thefluorescent body substrate. The fluorescent layer of the fluorescentplate is stuck on a photo-sensor substrate. The fluorescent layer has aninclination surface provided in an outer circumferential portion.According to the inclination surface, a flow of an adhesive is improved.As a result, accumulation of air bubbles is reduced.

Patent Literature 2 discloses a scintillator panel. The scintillatorpanel has a structure in which a substrate, a fluorescent body layer,and a protective film layer are laminated. When a scintillator panel isproduced, first, a laminated structure is formed utilizing coatingand/or vapor deposition. Next, the laminated structure is cut using apaper cutter. As a result, a scintillator panel having a desired shapeis obtained.

Patent Literature 3 discloses a radiation detection panel. The radiationdetection panel has a glass substrate in which a photoelectricconversion element is provided, and a fluorescent body layer which isformed on the glass substrate. Specifically, the fluorescent body layeris formed on a front surface and at least one side surface of the glasssubstrate. An angle between the front surface and at least one sidesurface is 90 degrees or smaller.

Patent Literature 4 discloses a solid-state X-ray detector. Thesolid-state X-ray detector has a photoelectric sensor and a scintillatorformed on the photoelectric sensor.

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Unexamined Patent Publication No.    2003-66150-   Patent Literature 2: Japanese Unexamined Patent Publication No.    2008-224422-   Patent Literature 3: Japanese Unexamined Patent Publication No.    2013-2887-   Patent Literature 4: Japanese Unexamined Patent Publication No.    2012-508873 of the PCT International Publication

SUMMARY OF INVENTION Technical Problem

As a laminated structure having a substrate and a functional layer,there is a scintillator panel having a substrate and a scintillatorlayer. A scintillator panel emits scintillation light in response toradiation incident on the scintillator layer. Here, when thescintillator panel is combined with a photo-detection substrate or thelike detecting scintillation light, its entirety exhibits a radiationdetection function.

When a scintillator panel is combined with a photo-detection substrate,first, a scintillator panel is molded to have a predetermined shape.Next, the molded scintillator panel and a photo-detection substrate areset. Thereafter, the two are bonded to each other, such that thescintillator panel and the photo-detection substrate are integrated. Asa result, a radiation detector is manufactured. At this time, adhesionis utilized in bonding of the scintillator panel and the photo-detectionsubstrate. In this manner, several steps of work are required inassembling of an apparatus utilizing a scintillator panel.

Here, an object of the present invention is to provide a scintillatorpanel in which damage to a scintillator panel during assembly work iscurbed, and a radiation detector.

Solution to Problem

According to an aspect of the present invention, there is provided ascintillator panel including a substrate portion having a first mainsurface and a first rear surface intersecting a first direction on sidesopposite to each other, and a first side surface extending such that thefirst main surface and the first rear surface are joined to each other;and a scintillator layer portion having a second rear surface formed ofa plurality of columnar crystals extending in the first direction andformed to include a base portion being on one end side of the columnarcrystals and facing the first main surface, a second main surface formedto include a tip portion on the other end side of the columnar crystals,and a second side surface extending such that the second main surfaceand the second rear surface are joined to each other. The first sidesurface and the second side surface are substantially flush with eachother. In the substrate portion, an angle between the first rear surfaceand the first side surface is smaller than 90 degrees.

In the scintillator panel, the angle between the first rear surface andthe first side surface of the substrate portion is smaller than 90degrees. Such a shape is formed by putting a cutting tool from thescintillator layer portion side into a laminated structure in which thesubstrate portion and the scintillator layer portion are laminated.Accordingly, cutting can be utilized in molding of a scintillator panel.As a result, the scintillator panel can be molded to have an arbitraryshape and an arbitrary size. Next, the first side surface of thesubstrate portion and the second side surface of the scintillator layerportion are made flush with each other, and the angle between the firstrear surface and the first side surface of the substrate portion issmaller than 90 degrees. As a result, the first side surface of thesubstrate portion further protrudes outward than the second side surfaceof the scintillator layer portion. According to this constitution, thesecond side surface of the scintillator layer portion is protected bythe first side surface of the substrate portion. Accordingly, it ispossible to curb damage due to an impact to the second side surface ofthe scintillator layer portion at the time of handling the scintillatorpanel.

In the aspect, the scintillator layer portion may generate scintillationlight. The substrate portion may absorb the scintillation light.According to this constitution, it is possible to employ a structure inwhich another substrate portion having a photo-detection function isbonded to the scintillator layer portion side.

In the aspect, the scintillator layer portion may generate scintillationlight. The substrate portion may reflect the scintillation light.According to this constitution, it is possible to employ a structure inwhich another substrate portion having a photo-detection function isbonded to the scintillator layer portion side.

In the aspect, the substrate portion may be formed of polyethyleneterephthalate. According to this constitution, a flexible scintillatorpanel can be formed. In addition, it is possible to easily prepare anabsorptive substrate or a reflective substrate with respect toscintillation light.

In the aspect, the second rear surface of the scintillator layer portionmay come into contact with the first main surface of the substrateportion. According to this constitution, it is possible to directly formthe scintillator layer portion on the first main surface of thesubstrate portion.

In the aspect, the scintillator panel may further include a barrierlayer formed to come into contact with each of the first main surface inthe substrate portion and the second rear surface in the scintillatorlayer portion. The barrier layer may be formed of thallium iodide. Thescintillator layer portion may be made of a material having cesiumiodide as a main component. The barrier layer formed of thallium iodideis resistant to moisture. Accordingly, when the barrier layer isprovided between the substrate portion and the scintillator layerportion, moisture percolating from the substrate portion side is blockedby the barrier layer. As a result, moisture reaching the scintillatorlayer portion is curbed. Accordingly, it is possible to protect the baseportion of the columnar crystals constituting the scintillator layerportion having deliquescent cesium iodide as the main component.

According to another aspect of the present invention, there is aradiation detector including the scintillator panel emittingscintillation light in response to incident radiation; and aphoto-detection substrate facing the scintillator panel and detectingthe scintillation light. According to this constitution, thescintillator panel is provided. As a result, work of sticking thescintillator panel on the photo-detection substrate can be easilyperformed. Accordingly, it is possible to easily assemble the radiationdetector.

Advantageous Effects of Invention

According to the present invention, there are provided a scintillatorpanel in which damage to a scintillator panel during assembly work iscurbed, and a radiation detector.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view illustrating a radiation image sensoraccording to an embodiment.

FIG. 2 is an enlarged cross-sectional view illustrating a main portionof the radiation image sensor illustrated in FIG. 1.

FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D are cross-sectional viewsillustrating main steps of manufacturing the radiation image sensor.

FIG. 4A, FIG. 4B, and FIG. 4C are cross-sectional views illustratingmain steps of manufacturing the radiation image sensor.

FIG. 5A, FIG. 5B, FIG. 5C, and FIG. 5D are cross-sectional viewsschematically illustrating a situation in which a scintillator panelbase body is cut.

FIG. 6 is an enlarged cross-sectional view illustrating a scintillatorpanel side surface.

FIG. 7 is an enlarged cross-sectional view illustrating a main portionof a scintillator layer.

FIG. 8 is an enlarged cross-sectional view illustrating main portions ofthe scintillator layer and a substrate.

FIG. 9 is an enlarged cross-sectional view illustrating the main portionof the substrate.

FIG. 10 is a perspective view schematically illustrating a situation ofthe scintillator layer including columnar crystals.

FIG. 11A is a cross-sectional view for describing an operation effect ofa scintillator panel according to the embodiment, and FIG. 11B is across-sectional view for describing an operation effect of ascintillator panel according to a comparative example.

FIG. 12A is a cross-sectional view for describing another operationeffect of the scintillator panel according to the embodiment, and FIG.12B is a cross-sectional view for describing an operation effect of thescintillator panel according to another comparative example.

FIG. 13A and FIG. 13B are cross-sectional views illustrating amodification example of the radiation image sensor.

FIG. 14 is a view illustrating another form of cutting the scintillatorpanel base body.

FIG. 15A, FIG. 15B, and FIG. 15C are cross-sectional views schematicallyillustrating a situation in which the scintillator panel base body iscut.

DESCRIPTION OF EMBODIMENT

Hereinafter, with reference to the accompanying drawings, an embodimentof the present invention will be described in detail. In description ofthe drawings, the same reference signs will be applied to the sameelements, and duplicate description will be omitted.

A scintillator panel according to the present embodiment convertsradiation such as X-rays into scintillation light such as visible light.The scintillator panel is applied to a radiation image sensor used in aradiation camera, for example.

As illustrated in FIG. 1, a radiation image sensor 1 serving as aradiation detector has a sensor substrate 2 (photo-detection substrate),a scintillator panel 10, and a moisture-proof sheet 3. These constituentelements are laminated in this order in a Z direction (first direction).

The sensor substrate 2 exhibits a rectangular shape in a plan view. Thesensor substrate 2 has a main surface 2 a, a rear surface 2 b, and aside surface 2 c. The sensor substrate 2 further has a plurality ofphotoelectric conversion elements 2 d provided on the main surface 2 a.The photoelectric conversion elements 2 d are disposed in atwo-dimensional manner along the main surface 2 a.

The scintillator panel 10 exhibits a substantially rectangular shape ina plan view. The scintillator panel 10 has a panel main surface 10 a, apanel rear surface 10 b, and a panel side surface 10 c. The scintillatorpanel 10 adheres to the main surface 2 a such that a part on the mainsurface 2 a of the sensor substrate 2 is covered. That is, thescintillator panel 10 is smaller than the sensor substrate 2.Specifically, the scintillator panel 10 is bonded to the main surface 2a with an adhesive 4 therebetween such that a region in which thephotoelectric conversion elements 2 d are disposed is covered. Detailsof the scintillator panel 10 will be described below.

The moisture-proof sheet 3 covers the entirety of the scintillator panel10 and a part of the sensor substrate 2. Specifically, themoisture-proof sheet 3 covers the panel rear surface 10 b and the panelside surface 10 c of the scintillator panel 10. The moisture-proof sheet3 covers a part of the main surface 2 a of the sensor substrate 2, thatis, a part surrounding the scintillator panel 10. A surrounding portion3 a of the moisture-proof sheet 3 adheres to the main surface 2 a of thesensor substrate 2. Due to this constitution, air-tightness of aninternal space covered by the moisture-proof sheet 3 is maintained.Accordingly, infiltration of moisture or the like into themoisture-proof sheet 3 from the outside is curbed.

The radiation image sensor 1 having the foregoing constitution receivesradiation R from the moisture-proof sheet 3 side, for example. Thescintillator panel 10 generates scintillation light in response toincidence of the radiation R. The sensor substrate 2 has thephotoelectric conversion elements 2 d disposed in a two-dimensionalmanner, and the photoelectric conversion elements 2 d generateelectrical signals in response to scintillation light. The electricalsignals are drawn out through a predetermined electric circuit. Then,based on the electrical signals, a two-dimensional image indicating anincident position and energy of radiation is generated.

The scintillator panel 10 will be described in detail. FIG. 2 is anenlarged cross-sectional view illustrating a side portion of thescintillator panel 10. The scintillator panel 10 has a substrate 11(substrate portion), a scintillator layer 12 (scintillator layerportion), and a protective film 13.

The substrate 11 is a resin plate member forming a base body of thescintillator panel 10. As an example, the substrate 11 is formed ofpolyethylene terephthalate (PET). When a PET substrate is used,flexibility can be applied to the scintillator panel 10. Moreover, workof bonding the scintillator panel 10 and the sensor substrate 2 becomeseasy. In addition, it is possible to comparatively easily prepare anabsorptive substrate or a reflective substrate with respect toscintillation light. As a result, the scintillator panel 10 havingpredetermined X-ray characteristics (brightness and resolution) can beformed. The substrate 11 has a substrate main surface 11 a (first mainsurface), a substrate rear surface 11 b (first rear surface), and asubstrate side surface 11 c (first side surface). The substrate mainsurface 11 a and the substrate rear surface 11 b are orthogonal to the Zdirection on sides opposite to each other. The substrate side surface 11c extends such that the substrate main surface 11 a and the substraterear surface 11 b are joined to each other. In other words, thesubstrate side surface 11 c intersects an X direction and a Y directionintersecting the Z direction.

The scintillator layer 12 receives the radiation R and generatesscintillation light. The scintillator layer 12 includes a plurality ofcolumnar crystals having cesium iodide (CsI) as a main component such asCsI:Tl (refer to FIG. 10). For example, the CsI content of thescintillator layer 12 may be within a range of 90% to 100%. In otherwords, when the CsI content of the scintillator layer 12 is 90% or more,it may be stated that the scintillator layer 12 has CsI as a maincomponent.

The scintillator layer 12 has a scintillator main surface 12 a (secondmain surface), a scintillator rear surface 12 b (second rear surface),and a scintillator side surface 12 c (second side surface). Thescintillator rear surface 12 b is formed of a plurality of base portionson one end side of the columnar crystals. The scintillator main surface12 a is formed of a plurality of tip portions on the other end side ofthe columnar crystals. The scintillator main surface 12 a and thescintillator rear surface 12 b are orthogonal to the Z direction onsides opposite to each other. In addition, the scintillator rear surface12 b faces the substrate main surface 11 a. That is, the scintillatorlayer 12 comes into direct contact with the substrate 11. In otherwords, no layer is interposed between the scintillator layer 12 and thesubstrate 11. The scintillator side surface 12 c extends such that thescintillator main surface 12 a and the scintillator rear surface 12 bare joined to each other. In other words, the scintillator side surface12 c intersects the X direction and the Y direction intersecting the Zdirection. The scintillator side surface 12 c is substantially connectedto the substrate side surface 11 c. Such constitutions of thescintillator side surface 12 c and the substrate side surface 11 c arereferred to as critical edges.

The protective film 13 covers the substrate 11 and the scintillatorlayer 12. The protective film 13 is a thin moisture-proof film. Theprotective film 13 is formed of parylene (polyparaxylene) or the like.Specifically, the protective film 13 is formed on the substrate rearsurface 11 b, the substrate side surface 11 c, the scintillator mainsurface 12 a, and the scintillator side surface 12 c.

A method for manufacturing the radiation image sensor 1 will bedescribed.

As illustrated in FIG. 3A, the substrate 11 is prepared. Next, asillustrated in FIG. 3B, the scintillator layer 12 is formed on thesubstrate main surface 11 a. Specifically, a fluorescent body material(for example, CsI:TI or CsBr:Eu) is subjected to vacuum vapor depositionon the substrate main surface 11 a. As a result, columnar crystals growon the substrate main surface 11 a.

As illustrated in FIG. 3C, a first film portion 13 a is formed. As anexample, the first film portion 13 a is formed of parylene. The firstfilm portion 13 a is formed on the substrate rear surface 11 b, thesubstrate side surface 11 c, the scintillator main surface 12 a, and thescintillator side surface 12 c. The first film portion 13 a enters gapsbetween the plurality of columnar crystals (refer to FIG. 10)constituting the scintillator layer 12. According to this constitution,the columnar crystals are protected by the first film portion 13 a. As aresult, damage to the columnar crystals in the next cutting step can becurbed. Through the foregoing steps, a scintillator panel base body 100is obtained.

A plurality of scintillator panels 10 are cut out from the scintillatorpanel base body 100. That is, the scintillator panel base body 100 iscut. In this cutting, a cutting method such as shear blade (two bladeson upper and lower sides, refer to FIGS. 14 and 15) type roller cutting,shearing, die-cutting, or push-cutting (upper single-blade) type (referto FIG. 5A) may be employed. As illustrated in a FIG. 3D, thescintillator panel base body 100 is disposed on a work table 101. Atthis time, the substrate rear surface 11 b faces the work table 101.According to this disposition, a cutting tool 102 is inserted from thescintillator layer 12 side.

As illustrated in FIG. 4A, a second film portion 13 b is formed. Similarto the first film portion 13 a, the second film portion 13 b may alsoemploy parylene. The panel side surface 10 c includes the substrate sidesurface 11 c and the scintillator side surface 12 c. Here, the secondfilm portion 13 b is formed such that at least side surfaces thereof arecovered. The second film portion 13 b may cover the first film portion13 a on the substrate rear surface 11 b and the first film portion 13 aon the scintillator main surface 12 a. The first film portion 13 a andthe second film portion 13 b constitute the protective film 13.

As illustrated in FIG. 4B, the scintillator panel 10 is stuck on thesensor substrate 2 which has been prepared in advance. First, the sensorsubstrate 2 is coated with the adhesive 4. Next, the scintillator panel10 is placed on the adhesive 4. At this time, the panel main surface 10a faces the main surface 2 a of the sensor substrate 2. Then, since thesubstrate side surface 11 c and the scintillator side surface 12 c areflush with each other, the adhesive 4 can flow favorably on the sidesurfaces thereof. Accordingly, it is possible to avoid a state where airbubbles stay in the adhesive 4. Then, the adhesive 4 is cured throughheating, using irradiation of ultraviolet rays, or the like. Then, asillustrated in FIG. 4C, the moisture-proof sheet 3 is attached. Throughthe foregoing steps, the radiation image sensor 1 is obtained. Theradiation image sensor 1 includes the moisture-proof sheet 3.

Accordingly, even if the scintillator panel 10 is bonded to the sensorsubstrate 2 without forming the protective film 13, the moisture-proofsheet 3 can prevent deliquescence of the scintillator layer.

As described above, the method for manufacturing the radiation imagesensor 1 and the scintillator panel 10 includes a step of cutting thescintillator panel base body 100. Here, cutting of the scintillatorpanel base body 100, and a cut surface (that is, the panel side surface10 c) will be described in detail with reference to FIGS. 5 to 10. InFIGS. 6 to 10, for the convenience of description, the verticaldirection is upside down with respect to the radiation image sensor 1illustrated in FIGS. 1 and 2.

When the scintillator panel 10 is cut by inserting the cutting tool 102from a side of the scintillator layer 12, a cut surface (panel sidesurface 10 c) as illustrated in FIG. 6 is formed. The panel side surface10 c includes the substrate side surface 11 c and the scintillator sidesurface 12 c.

As already described above, the scintillator side surface 12 c issubstantially connected to the substrate side surface 11 c. That is, thescintillator side surface 12 c is substantially flush with the substrateside surface 11 c. Here, the expression “flush with each other” denotesthat when the substrate side surface 11 c and the scintillator sidesurface 12 c are viewed in a macroscopic manner, each of the surfaces isincluded in the same virtual plane K1. As will be described below, thesubstrate side surface 11 c and the scintillator side surface 12 c haveminute uneven structures such as an undercut, a coarse surface, or burrswhen viewed in a microscopic manner. However, when they are defined tobe “flush with each other”, the uneven structures are disregarded. Inaddition, the expression “substantially flush with each other” meansthat the substrate side surface 11 c and the scintillator side surface12 c do not have to be completely included in the same plane. Forexample, a predetermined width need only be defined based on the virtualplane K1, such that the substrate side surface 11 c and the scintillatorside surface 12 c are settled on an inner side of the width. In otherwords, for example, as illustrated in FIG. 11B and FIG. 12B, theexpression “substantially flush with each other” means that none of thesubstrate side surface 11 c and the scintillator side surface 12 c is ina form of further protruding than the other.

When the substrate 11 is viewed in the Y direction, the panel sidesurface 10 c is not perpendicular. In other words, the panel sidesurface 10 c is tilted with respect to the Z direction. Morespecifically, the substrate side surface 11 c constituting the panelside surface 10 c is tilted with respect to the Z direction.

More specifically, an angle A1 between the substrate rear surface 11 band the substrate side surface 11 c is smaller than 90 degrees. In otherwords, the angle A1 is 82 degrees or larger. In addition, the angle A1is 88 degrees or smaller. As an example, the angle A1 is approximately85 degrees. An angle A2 between the Z direction and the substrate sidesurface 11 c is within a range larger than zero degrees to 8 degrees. Inaddition, the angle A2 is 2 degrees or larger. The substrate sidesurface 11 c and the scintillator side surface 12 c defined by theangles A1 and A2 are inclined toward the centers of the substrate 11 andthe scintillator layer 12. When the angles A1 and A2 are defined,similar to the expression “flush with each other” described above,uneven structures formed on the substrate side surface 11 c aredisregarded. That is, when the angles A1 and A2 are defined, thesubstrate side surface 11 c may be replaced as the virtual plane K1described above. In this case, the angle A1 is an angle between thesubstrate rear surface 11 b and the virtual plane K1 of which minuteuneven structures are disregarded.

FIG. 7 illustrates a cross section of a corner portion of thescintillator main surface 12 a and the scintillator side surface 12 c ofthe scintillator layer 12. That is, FIG. 7 is an enlarged view of a partM2 in FIG. 6. A region having a curved surface shape referred to as anundercut 12 d is formed in the corner portion of the scintillator layer12.

When the scintillator panel base body 100 is cut, the cutting tool 102is first pushed against the first film portion 13 a (refer to FIG. 5A).At this time, the cutting tool 102 is not in contact with thescintillator layer 12. Then, if the cutting tool 102 is further thrust,the cutting tool 102 cuts the first film portion 13 a while slightlysquashing the first film portion 13 a. Internal stress due to thissquashing also arrives at a part 12 e of the scintillator layer 12 wherethe cutting tool 102 has not arrived. Consequently, until the cuttingtool 102 arrives at the scintillator layer 12, columnar crystals formingthe part 12 e included in the scintillator main surface 12 a areslightly destroyed and become deficient due to the internal stress. Thispart in which columnar crystals become deficient forms the undercut 12 d(refer to FIG. 10).

When the cutting tool 102 arrives at the scintillator layer 12 (refer toFIG. 5B), the scintillator layer 12 is cut by the sharp cutting tool102. The scintillator layer 12 includes a plurality of columnar crystalsextending in the Z direction. As a result, the cutting tool 102 movesdownward while breaking a part of the columnar crystals. This breakageof the columnar crystals may occur irregularly. Accordingly, when abroken surface (that is, the scintillator side surface 12 c) of thescintillator layer 12 is viewed in a microscopic manner, the brokensurface is formed of a plurality of columnar crystals which areirregularly broken. Accordingly, the scintillator side surface 12 cbecomes a coarse surface 12 ca in a microscopic manner (refer to FIG.10). For example, the expression “a coarse surface” stated hereinindicates a surface having more significant unevenness than a surfacewhich has no lack of columnar crystals and in which columnar crystalsare regularly arranged.

As illustrated in FIG. 8, in cutting performed by the cutting tool 102,when the thickness of the scintillator layer 12 becomes comparativelylarge (for example, 200 μm or larger), a notch 12 f may be generated onthe scintillator rear surface 12 b of the scintillator layer 12. Thisnotch 12 f is formed due to a part in which the base portion of thecolumnar crystals becomes deficient (refer to FIG. 10).

The second film portion 13 b provided after cutting enters the undercut12 d, the coarse surface 12 ca, and the notch 12 f. Specifically, thesecond film portion 13 b enters minute gaps generated due to deficiencyof columnar crystals. Therefore, according to this constitution,adhesion of the second film portion 13 b with respect to thescintillator side surface 12 c is improved.

The cutting tool 102 cuts the substrate 11 while moving furtherdownward. In an initial stage (refer to FIG. 5C) of the cutting processof the substrate 11, the thickness of the substrate 11 is comparativelylarge. Accordingly, the substrate 11 is not bent due to a force ofpressing the cutting tool 102 downward, and the substrate 11 is cut bythe cutting tool 102. A surface formed in this process is a shearsurface which is comparatively smooth. In a later stage (refer to FIG.5D) of the cutting process, the thickness of the substrate 11 becomescomparatively small. Accordingly, the substrate 11 cannot withstand theforce of pressing the cutting tool 102 downward. As a result, thesubstrate 11 is divided due to the force. The state (refer to FIG. 9, apart M3 in FIG. 6) of the front surface of a surface formed in thisprocess is a coarse surface 11 d (broken surface) which is comparativelycoarse. A burr 11 e is formed at a lower end of the coarse surface 11 d.Accordingly, on the substrate side surface 11 c, a smooth surface and acoarse surface are present side by side along the proceeding directionof the cutting tool 102. That is, a region far from the scintillatorlayer 12 on the substrate side surface 11 c has coarser surface than aregion closer to the scintillator layer 12. The coarse surface 12 ca onthe scintillator side surface 12 c is not connected to the coarsesurface 11 d on the substrate side surface 11 c. That is, acomparatively smooth part of the substrate side surface 11 c is presentbetween the coarse surface 12 ca and the coarse surface 11 d. Inaddition, for example, the burr 11 e is a sharp part further protrudingthan the substrate rear surface 11 b on the substrate side surface 11 c.

Hereinafter, operation effects of the scintillator panel 10 and theradiation image sensor 1 according to the present embodiment will bedescribed.

In the scintillator panel 10, the angle A1 between the substrate rearsurface 11 b and the substrate side surface 11 c of the substrate 11 issmaller than 90 degrees. Such a shape is formed by putting the cuttingtool 102 from the scintillator layer 12 side into a laminated structurein which the substrate 11 and the scintillator layer 12 are laminated.Accordingly, cutting can be utilized in molding of a scintillator panel.As a result, the scintillator panel 10 can be molded to have anarbitrary shape and an arbitrary size.

The substrate side surface 11 c of the substrate 11 and the scintillatorside surface 12 c of the scintillator layer 12 are flush with eachother, and the angle A1 between the substrate rear surface 11 b and thesubstrate side surface 11 c of the substrate 11 is smaller than 90degrees. The substrate side surface 11 c of the substrate 11 furtherprotrudes outward than the scintillator side surface 12 c of thescintillator layer 12. In other words, the substrate 11 has a partpresent on a side outward from the scintillator layer 12. According tothis constitution, the scintillator side surface 12 c of thescintillator layer 12 is protected by the substrate side surface 11 c ofthe substrate 11.

FIG. 11A illustrates the scintillator panel 10 according to theembodiment, and FIG. 11B illustrates a scintillator panel 200 accordingto a comparative example. According to FIG. 11B, a part 202 d on a sidesurface 202 c of a scintillator layer 202 further protrudes than asubstrate side surface 201 c of a substrate 201. According to such aconstitution, for example, when the scintillator panel 200 approachesrelatively closer to a flat plate 210, a protective film 213 on the part202 d of the scintillator layer 202 abuts first. Since the internalstress due to the abutment acts on the protruding part 202 d of thescintillator layer 202, the scintillator layer 202 is likely to bedamaged. On the other hand, according to FIG. 11A, when the scintillatorpanel 10 approaches relatively closer to the flat plate 210, theprotective film 13 on the substrate side surface 11 c of the substrate11 abuts first. Accordingly, the protective film 13 on the substrateside surface 11 c abuts earlier than the protective film 13 on thescintillator side surface 12 c. As a result, damage to the scintillatorlayer 12 due to a collision can be reduced. Accordingly, in the case ofthe scintillator panel 10 according to the embodiment, damage due to animpact to the scintillator side surface 12 c at the time of handling iscurbed.

The substrate side surface 11 c of the substrate 11 and the scintillatorside surface 12 c of the scintillator layer 12 are flush with eachother. Accordingly, when the scintillator panel 10 is bonded to anothercomponent using the adhesive 4, the adhesive 4 flows favorably.

As a result, occurrence of accumulation of air bubbles is curbed.Therefore, according to the scintillator panel 10, bonding work withrespect to a photo-detection substrate can be easily performed.

FIG. 12A illustrates the scintillator panel 10 according to theembodiment, and FIG. 12B illustrates a scintillator panel 300 accordingto another comparative example. According to FIG. 12B, a side surface301 c of a scintillator layer 301 and a side surface 302 c of asubstrate 302 are not flush with each other. In this case, a regionsurrounded by a sensor substrate 310, the scintillator layer 301, andthe substrate 302 is formed. Then, when the scintillator panel 300adheres to the sensor substrate 310, an adhesive 304 tends to stay inthe region. As a result, air bubbles 320 included in the adhesive 304are likely to stay in a corner portion between the scintillator layer301 and the substrate 302. In a case where such staying is expected,execution of processing such as degassing is examined. On the otherhand, such a region of the scintillator panel 300 in the comparativeexample is not formed in the scintillator panel 10 illustrated in FIG.12A. That is, the adhesive 4 is not retained in a predetermined region.Accordingly, adhesive workability between the scintillator panel 10 andthe sensor substrate 2 can be improved.

According to the radiation image sensor 1 including the scintillatorpanel 10, work of sticking the scintillator panel 10 on the sensorsubstrate 2 can be easily performed. Accordingly, the radiation imagesensor 1 can be easily assembled.

The scintillator panel 10 and the radiation image sensor 1 according tothe present embodiment can also exhibit operation effects as follows.

The scintillator panel 10 includes the substrate 11 and the scintillatorlayer 12. The substrate side surface 11 c of the substrate 11 partiallyhas a coarsened region (coarse surface 11 d). According to this coarsesurface 11 d, the contact area between the substrate 11 and theprotective film 13 increases. In addition, the scintillator side surface12 c of the scintillator layer 12 has the coarse surface 12 ca which isa coarsened region including uneven structures. According to this coarsesurface 12 ca, the contact area between the scintillator layer 12 andthe protective film 13 increases. Adhesion of the protective film 13 isenhanced as the contact area increases. Accordingly, in the scintillatorpanel 10, adhesion between the substrate 11 and the protective film 13and adhesion between the scintillator layer 12 and the protective film13 can be improved.

Uneven structures of the coarse surface 12 ca are formed when thecolumnar crystals become partially deficient. The scintillator sidesurface 12 c having such a constitution is obtained by cutting alaminated structure having the scintillator layer 12 and the substrate11. Accordingly, the coarse surface 12 ca having uneven structures canbe formed easily.

The substrate side surface 11 c includes the burr 11 e formed in acorner portion between the substrate rear surface 11 b and the substrateside surface 11 c. According to this constitution, the contact areabetween the substrate 11 and the protective film 13 increases.Accordingly, in the scintillator panel 10, adhesion between thesubstrate 11 and the protective film 13 can be improved.

The scintillator layer 12 has the notch 12 f formed in a corner portionbetween the scintillator rear surface 12 b and the scintillator sidesurface 12 c. The notch 12 f is filled with the protective film 13.According to this constitution, the contact area between thescintillator layer 12 and the protective film 13 further increases.Furthermore, the contact area between the substrate 11 and theprotective film 13 further increases as well. Accordingly, in thescintillator panel 10, adhesion with respect to the protective film 13can be further improved.

The scintillator layer 12 has the undercut 12 d formed in a cornerportion between the scintillator main surface 12 a and the scintillatorside surface 12 c. The undercut 12 d is filled with the protective film13. According to this constitution, the contact area between thescintillator layer 12 and the protective film 13 still furtherincreases. Accordingly, in the scintillator panel 10, adhesion withrespect to the protective film 13 can be still further improved.

The radiation image sensor 1 includes the scintillator panel 10.Accordingly, adhesion between the scintillator layer 12 and theprotective film 13 is improved, and the moisture resistance can beenhanced.

Hereinabove, an embodiment of the present invention has been described.However, the present invention is not limited to the foregoingembodiment and can be performed in various forms.

For example, in the scintillator panel 10 according to the forgoingembodiment, the scintillator layer 12 is formed on the substrate 11.That is, the scintillator rear surface 12 b comes into direct contactwith the substrate main surface 11 a. The scintillator panel 10 is notlimited to such a constitution.

As illustrated in FIG. 13A, in addition to a substrate 11A and thescintillator layer 12, a scintillator panel 10A included in a radiationimage sensor 1A may further include an additional layer havingadditional function. Examples of an additional layer include a barrierlayer 16 formed between the substrate 11A and the scintillator layer 12.According to this constitution, the scintillator panel 10A has alaminated structure in which the substrate 11A, the barrier layer 16,and the scintillator layer 12 are laminated in this order. That is, thescintillator layer 12 is formed on the substrate main surface 11 a withthe barrier layer 16 therebetween.

The barrier layer 16 is a layer, for example, having thallium iodide(TII) as a main component. For example, the TII content of the barrierlayer 16 may be within a range of 90% to 100%. In other words, when theTII content of the barrier layer 16 is 90% or more, it may be statedthat the barrier layer 16 has TII as a main component. The barrier layer16 has properties such that moisture is unlikely to pass therethrough.For example, when moisture has percolated from the substrate 11A side,movement of the moisture to the scintillator layer 12 is hindered by thebarrier layer 16. Therefore, according to the scintillator panel 10Ahaving the barrier layer 16, deliquescence of columnar crystalsconstituting the scintillator layer 12 due to moisture can be curbed.

Such a constitution is particularly effective in a case where thesubstrate 11A has an organic layer which moisture easily penetrates. Asubstrate having an organic layer stated herein may be the substrate 11Aconstituted of a base body 11 m made of a material (metal, carbon,glass, or the like) different from an organic material, and an organiclayer 11 r made of an organic material (xylylene resin, acrylic resin,silicone resin, or the like). In addition, as illustrated in FIG. 13B, asubstrate having an organic layer may be a substrate 11B constituted ofa base body 11 s made of an organic material (polyethyleneterephthalate, polyethylene naphthalate, polyester,polyetheretherketone, polyimide, or the like).

A predetermined optical function may be applied to a substrate of thescintillator panel 10. Specifically, functions such as light absorptionproperties, light transmission properties, or light reflectionproperties may be selectively applied to a substrate. For example, whenlight reflection properties are applied to a substrate, titaniumdioxide, alumina, yttrium oxide, or zirconium oxide (reflective pigment)is added to PET which is a main material of the substrate. In addition,as another example of a case where light reflection properties areapplied to a substrate, a light reflective layer including thereflective pigment described above and a binder resin may be formed on abase body having PET as a main material.

As illustrated in FIG. 14, in cutting of the scintillator panel basebody 100, shear blade cutting (two blades on upper and lower sides) typeas described above may be employed. This type utilizes an upper blade103 and a lower blade 104. As illustrated in FIG. 15A, FIG. 15B and FIG.15C, first, the scintillator panel base body 100 is disposed on thelower blade 104. Strictly speaking, a blade portion of the lower blade104 is a corner portion. The scintillator panel base body 100 isdisposed such that the corner portion is covered (refer to FIG. 15A).Next, the upper blade 103 is input from the scintillator layer 12 side(refer to FIG. 15A and FIG. 15B). Then, when the upper blade 103 arrivesat the corner portion of the lower blade 104, the scintillator panelbase body 100 is cut (refer to FIG. 15C).

REFERENCE SIGNS LIST

-   -   1 Radiation image sensor    -   2 Sensor substrate (photo-detection substrate)    -   2 a Main surface    -   2 b Rear surface    -   2 c Side surface    -   2 d Photoelectric conversion element    -   3 Moisture-proof sheet    -   3 a Surrounding portion    -   4 Adhesive    -   10, 10A Scintillator panel    -   10 a Panel main surface    -   10 b Panel rear surface    -   10 c Panel side surface    -   11, 11A Substrate (substrate portion)    -   11 a Substrate main surface (first main surface)    -   11 b Substrate rear surface (first rear surface)    -   11 c Substrate side surface (first side surface)    -   11 d Coarse surface    -   11 e Burr    -   11 s Base body    -   11 r Organic layer    -   11B Substrate    -   11 m Base body    -   12 Scintillator layer (scintillator layer portion)    -   12 a Scintillator main surface (second main surface)    -   12 b Scintillator rear surface (second rear surface)    -   12 c Scintillator side surface (second side surface)    -   12 ca Coarse surface    -   12 d Undercut    -   12 f Notch    -   13 Protective film    -   13 a First film portion    -   13 b Second film portion    -   16 Barrier layer    -   100 Scintillator panel base body    -   101 Work table    -   102 Cutting tool    -   A1, A2 Angle    -   K1 Virtual plane    -   R Radiation

1. A scintillator panel comprising: a substrate portion having a firstmain surface and a first rear surface intersecting a first direction onsides opposite to each other, and a first side surface extending suchthat the first main surface and the first rear surface are joined toeach other; and a scintillator layer portion having a second rearsurface formed of a plurality of columnar crystals extending in thefirst direction and formed to include a base portion being on one endside of the columnar crystals and facing the first main surface, asecond main surface formed to include a tip portion on the other endside of the columnar crystals, and a second side surface extending suchthat the second main surface and the second rear surface are joined toeach other, wherein the first side surface and the second side surfaceare substantially flush with each other, and wherein in the substrateportion, an angle between the first rear surface and the first sidesurface is smaller than 90 degrees.
 2. The scintillator panel accordingto claim 1, wherein the scintillator layer portion generatesscintillation light, and wherein the substrate portion absorbs thescintillation light.
 3. The scintillator panel according to claim 1,wherein the scintillator layer portion generates scintillation light,and wherein the substrate portion reflects the scintillation light. 4.The scintillator panel according to claim 1, wherein the substrateportion is formed of polyethylene terephthalate.
 5. The scintillatorpanel according to claim 1, wherein the second rear surface of thescintillator layer portion comes into contact with the first mainsurface of the substrate portion.
 6. The scintillator panel according toclaim 1, further comprising: a barrier layer formed to come into contactwith each of the first main surface in the substrate portion and thesecond rear surface in the scintillator layer portion, wherein thebarrier layer is formed of thallium iodide, and wherein the scintillatorlayer portion is made of a material having cesium iodide as a maincomponent.
 7. A radiation detector comprising: a scintillator panelaccording to claim 1 emitting scintillation light in response toincident radiation; and a photo-detection substrate facing thescintillator panel and detecting the scintillation light.